As a way of transmitting sound, bone-conduction achieves sound transmission by converting a sound signal into mechanical vibration signals of different frequencies, and sound waves being transmitted through the skull, the bony labyrinth, the endolymphe, the spiral organ, the auditory nerve, and the auditory center of a human. Compared to the classic sound transmission manner of generating sound waves by the eardrum, bone-conduction omits many steps of transmitting sound waves, also, sound can be reproduced clearly in a noisy environment, and the sound waves will not affect other persons due to sound diffusion in the air.
Although there are sound transmission devices using bone-conduction at present, the listening effect is greatly affected, since the sound transmitted by the conventional bone-conduction sound transmission devices will suffer from attenuation when passing through mediums such as the skin, soft tissue and skeleton of human body, which may result in a rather larger sound distortion between the sound heard by a user and the sound that reaches the user through air conduction.